'A darned shame': Democrats hoped one thing would be the key toward unity — but many Bernie supporters aren't buying it

Bernie Sanders. Alex Wong/Getty Images PHILADELPHIA — Sen. Bernie Sanders' top surrogates at the Democratic National Convention on Monday had a not-so-subtle plea for unity to die-hard "Bernie or bust" delegates: Remember the party platform.

Throughout the first day of the convention, high-profile Sanders proponents touted the concessions that Democratic Party leadership made to the Vermont senator's supporters in reforming the platform, the formal set of goals that were officially adopted by the party on Monday.

Maine state Rep. Diane Russell touted the Democratic National Committee's decision to consider removing superdelegates, Democratic Party officials whose votes play a small role in selecting presidential candidates.

Introducing Sanders at the convention on Monday, former Sanders surrogate Rep. Keith Ellison of Minnesota noted the ways the Sanders campaign influenced the official Democratic Party platform. He mentioned the adoption of provisions like support for a $15 federal minimum wage and heavy regulations on hydraulic fracturing, a process that environmentalists deride for its side effects.

"Tonight, we are united around the most progressive platform in history," Ellison said.

"That's the platform that we can make the law of the land if we stand together, if we work together, and if we vote together on November 8," he added.

But that didn't seem to placate some Sanders delegates and grassroots supporters as Hillary Clinton moved toward accepting the Democratic presidential nomination this week at the convention.

Many of the senator's delegates in the hall were still incensed that the party platform refused to adopt official language opposing the Trans-Pacific Partnership, a multinational trade deal supported by the Obama administration but opposed by many in both parties for its potential effects on American manufacturing and jobs.

When the Democratic Rules Committee took its vote early in the evening, many Sanders supporters booed the platform, voting "nay" when it was put up for a so-called voice vote.

Chris, an alternate delegate for Sanders, told Business Insider it was "a darned shame" that Democrats weren't more vocally opposing TPP.

"They completely ignored it. We had signs: 'No TPP.' Elijah completely ignored it. And a lot of people felt slighted from it, and a lot of people felt hurt and afraid," he said, referring to Rep. Elijah Cummings of Maryland.

A Sanders supporter at day one of the Democratic National Convention in Philadelphia. Reuters/Lucy Nicholson

Sanders supporters were also not impressed by a slick video about the party platform that played on the Jumbotron, highlighting the leftward tilt of the platform.

Dean Vanderstone, a Sanders delegate from Michigan, told Business Insider that while he was pleased with some of the changes in the platform he thought the whole convention was "a farce."

"It wasn't as smooth and clean and kumbaya as you heard from the speakers," Vanderstone said of the platform drafting committee, noting his discussions with Sanders supporters on the rules and drafting committees. "There was a lot of dissension."

Still, as the Clinton campaign scrambled to placate delegates, moving Sanders into a prime-time speaking slot on Monday night, many were more hopeful about party unity going forward.

"There's a lot of great energy. Sen. Sanders has been fantastic about helping to unify the party," Secretary of Housing and Urban Development Julian Castro told Business Insider, noting that he was speaking in his personal capacity as a Clinton supporter. "I'm confident that he'll do it tonight. And I'm confident in November we'll have an overwhelming Democratic turnout to defeat Donald Trump."

He added: "Bernie provided a tremendous positive voice for change. And Hillary has embraced so much of the policy positions and the spirit of Bernie's campaign. So the ground is set for us to move forward as a united Democratic Party."

Sanders ended the night with a strong call for unity amid the day of relative chaos with that prime-time speech, closing out the night with a forceful endorsement of Clinton.

Sanders said: "Hillary Clinton will make an outstanding president, and I am proud to stand with her here tonight."